Signs that MWF may no longer be safe to use

Millions of workers engaged in manufacturing parts are exposed to metalworking fluids (MWFs). Metalworking fluids are in widespread, high volume use for their coolant, lubricant, and corrosion resistant properties during machining operations. These fluids are complex mixtures of oils, detergents, surfactants, biocides, lubricants, anti-corrosive agents, and other potentially toxic ingredients. There are many signs that a MWF has undergone changes and is no longer safe to use because of emerging health hazards. If one or more of the following changes occur, the fluid should be evaluated to see if it is safe for continued use or if it should be replaced. Check the sump level at the start of the shift. A low sump level, 30% below the full mark, shows metalworking fluid loss or water evaporation (increasing the concentration of chemicals present in the MWF). Check the concentration. If too strong, add water to reach the proper concentration. If the concentration is correct then fluid was lost due to drag-out. You should add fluid at an appropriate dilution, or if pre-diluted fluid is not available, water and concentrate can be added. All systems should be monitored carefully and metalworking fluid additions should be made on a regular basis to maintain a constant working concentration. The correct concentration should be verified when finished. Determine if the fluid colour looks normal. When in good condition many synthetic fluids are clear, semi-synthetics are often transparent to milky, and soluble oil usually looks milky white with no free oil layer. If the fluid turns grey or black, then bacteria are often present. If the fluid picks-up a yellow or brown tint then tramp oil may be present. Dye fading may indicate that a fluid is aging. When fluids smell bad, it usually means that there is uncontrolled microbial growth. Although it may be possible to cover up the odour, it's best to address the cause because microorganisms present in the fluid can be aerosolised into the air as part of the mist. Exposure to microorganisms in the air may cause adverse health effects to exposed employees. If the fluid has a strong and "locker room" odour, it likely has biological growth and should be treated with biocide and evaluated. If need be, the fluid should then be discarded, the sump properly cleaned, and the fluid replaced. If the fluid has floating chips, swarf, or mould growth, this is not normal. Try to remove as much as possible with a skimmer or have it pumped off. The level of dirt (total suspended solids) in the fluid is a measure of the efficiency of the filtering system. Periodic checks and maintenance of the filtration system and oil skimmer are necessary to assure that they are functioning as designed. With water-diluted fluids, if the sump is completely covered with oil and the machinist cannot swish the oil out of the way for more than 5 to 8 seconds before the sump is covered again, there is too much tramp oil present. Skim or pump the surface oil to remove it. Tramp oil is one of the main causes of dermatitis. These oils are not developed with repeated skin contact in mind, and some components of these machine lubricants are highly irritating to the skin. Unemulsified (tramp) oils can be a significant carrier of metallic fines, which can be deposited on the skin and cause mechanical irritation. These fines, suspended by tramp oil, are a major cause of dermatitis. A lot of foam may be caused by soft water with some products. The fluid may also be too highly concentrated, or it may be contaminated by cleaners, or there may be an imbalance in the fluid surfactants. Another possibility is that you could have an undersized system, excessive flow rates, or the fluid may not be at rest long enough to allow air to escape. In addition, the level of cutting fluid in the reservoir may be low, causing air to be drawn into the pump. This couldAir Jordan 30.5 Shoes